In recent years rapidly increased consumption of natural petroleum products, particularly gasoline, and the consequent diminution of natural petroleum reserves have become serious problems throughout the world. Conservation measures, as well as research for substitute fuels and other sources of energy, have become of paramount importance and a wide variety of programs have been under consideration and actually commenced in order to solve these fundamental problems. Among such programs are many which deal with motor fuels, including the search for new fuels, alteration of presently known fuels, improved fuel manufacturing processes, the development of new types of engines and, as well, efforts to make current engines more efficient while consuming less fuel.
The technology for altering presently known motor fuels has been known for some time. For example, the mixing of gasoline and alcohol and gasoline, alcohol and/or water to provide a suitable motor fuel for internal combustion engines has been known for many years. However, such fuels have heretofore never become widely commercially acceptable because of the ready availability of gasoline derived from natural petroleum at relatively acceptable prices. The dwindling supply of natural petroleum and increased prices of the same in recent times, however, have made such altered fuels more attractive.
Among such altered fuels one of the most suitable for use in internal combustion engines is gasoline containing alcohol. This is especially so since alcohol not only has good combustion properties but is also readily available from a wide variety of sources such as, for example, grains, as an industrial by-product, and also a product of waste materials. This is particularly true with respect to ethanol per se.
On the other hand, it is known that alcohol, and particularly ethanol, forms an azeotrope with water and cannot be completely separated from such water by simple distillation procedures. Commercial plants generally produce ethanol containing 6% to 7% water by weight which, when mixed with gasoline in the range of about 10% alcohol and 90% gasoline, forms two liquid phases.
Consequently, the usual procedure in making an alcohol-gasoline mixture is to first remove the water from commercially manufactured alcohol by using an entrainer and then mixing the dry alcohol with a suitable motor fuel such as gasoline, the combined product being generally referred to as gasohol. For example, a typical process system for making gasohol includes a dehydration drying column and a stripper or recovery column, employing benzene or other suitable material which forms a ternary azeotrope with aqueous alcohol as an entrainer to remove water from commercial alcohol, the anhydrous alcohol subsequently being mixed with gasoline to form gasohol. However, such a system is not only relatively complex but must also be carefully balanced with the entrainer in order to give an anhydrous alcohol as a bottoms product, as explained more fully hereinafter. Therefore, presently known systems and processes for making gasohol are disadvantageous for the reasons mentioned above and there exists a need for a process for making motor fuel containing alcohol which does not have the inherent disadvantages previously mentioned.
For the alcohol producer it is desirable to make a fuel product directly instead of making alcohol and then dehydrating it. In the United States of America the alcohol must be made under government supervision and present procedures call for a government agent to check the quantity of 190 proof or higher spirits produced and as well, to be present when a denaturant is added to the alcohol. Special denaturing formulas and regulations require that the alcohol may only be shipped in bond to another bonded premises where it is used to make vinegar, diethyl ether, protein extractant or the like, or that the alcohol be completely denatured under government supervision. Completely denatured formulations must be prepared under supervision and only then may the product be removed from the premises without restrictions. The two completely denatured formulations, Formula #18 and Formula #19, presently specified by BATF (Bureau Alcohol and Tax Formula) Regulations call for the addition of certain materials to every 100 gallons of spirit. For example, Formula #18 calls for the addition of 2.5 gal methylisobutyl ketone, 0.125 gallon pyronate and 1.0 gallon of gasoline or kerosene for every 100 gallons of spirit. On the other hand, Formula #19 calls for the addition of 4 gallons methylisobutyl ketone and 1 gallon of gasoline or kerosene. In view of the present Gasohol Programs in the United States, recent regulations provide that alcohol containing at least 10 % gasoline will be classified as completely denatured and thus be permitted to be removed from a distillery without restriction.
It is, therefore, a primary object of this invention to provide an energy efficient process for the production of an anhydrous alcohol product containing 85% to 90% alcohol with the remainder being conventional service station non-leaded gasoline, such product being made directly from fermented stock without the possibility of withdrawing or recovering an uncontaminated alcohol from the system.
It is another object of the invention to provide such a process without the possibility of contaminating the distillery grains or other feed stock residue of fermentation with the gasoline used in the process.
It is still a further object of the invention to provide a process which provides a product which will classify as completely denatured and thus one which may be removed from the manufacturing premixes without restriction, thus obviating the necessity for denaturing of the product in the presence of the BATF agent.
It is still another object of the invention to provide a process for the direct production from fermented stock of an anhydrous alcohol product containing 85% to 90% by weight alcohol, the remainder being conventional non-leaded gasoline, such as may be readily obtained directly from automotive gasoline stations or bulk supply terminals as the residue.
A still further object of the invention is the provision of a process which encompasses an entire plant process to satisfactorily produce an alcohol for fuel from a fermented feed containing alcohol in the usual concentration of up to about 12 volume % alcohol.
Other objects of this invention will be readily apparent from the following description thereof which is to be taken in conjunction with the accompanying drawings.